The screw nailer is an assisting device that can be installed on the end of pneumatic or electrical tool, and it is designed to move the screws along the process, so that operators do not have to hold the screws, which makes it safer, more effective and labor-saving.
Please see FIGS. 1-2 for the conventional structure of this screw nailer, which comprises a body 10, a driving wheel 11, a one-way bearing 12, a guide driving rod 13 and a snap 14; please see FIG. 2 for its operation, when the guide driving rod 13 is driven and turning, it moves the one-way bearing 12 along, and the one-way bearing turns the driving wheel 11 in one direction in a path with preset angle, at this time, the coiled wedge end 141 of the snap 14 mentioned above is locked in the fixation slot 112 formed between the protruding blocks 111 after an elastic recoil is created when it moves along the protruding block 111 on the driving wheel 11; when this move is completed, it would also moves the nail belt 15 by moving the protruding teeth 113 of the driving wheel 11 synchronously; except, this convention structure still has the following issues existed in practical application.
Because when the nail belt 15 moves, the fixed position is achieved by locking the coiled wedge end 141 of the snap 14 in the fixation slot 112 of the driving wheel 11; however, after the snap 14 has been used for a while, it may become crooked and cause elastic fatigue, thus, the stability and endurance of the snap's locking movement becomes gradually degenerated and could not meet the requirement, and “over-turn” appears at the end of each turn of the driving wheel 11, which causes the driving wheel 11 to fail to position the nail belt 15 in the designated location, so that it is easy to nail the screws, which are on the nail belt, to the wrong position, and this affects the coming nailing movement, because slightly dispositioned nail can easily cause the nailing target to look crooked, and further affect its quality besides it may disrupt the process of nail positioning.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement if the art to provide an improved structure that can significantly improve the efficacy.
To this end, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.